1. Field of the Invention
The present invention relates to an ink jet recording ink with excellent antiseptic and antifungal properties.
2. Description of the Related Art
Ink jet recording is a method for recording text or graphics on a recording medium surface by discharging droplets of ink from a fine nozzle. Some of the ink jet recording methods that have seen practical use include a method in which an electrostrictive element is used to convert an electrical signal into a mechanical signal, ink stored in the nozzle head portion is intermittently discharged, and text or symbols are recorded on the recording medium surface, and a method in which the part of the ink stored in the nozzle head portion that is extremely close to the discharge area is rapidly heated to create bubbles and is intermittently discharged by the volumetric expansion produced by these bubbles, so that text or symbols are recorded on the recording medium surface.
The ink used in this ink jet recording must be a type that can be discharged stably over extended periods of time. Therefore, it is imperative that no bacteria, mold, or other microbes be generated. There is no particular problem with non-aqueous inks, but bacteria, mold, or other microbes are frequently found in aqueous inks. In view of this, isothiazolone-based compounds have been used as antiseptics in the past. There are many instances of using isothiazolone-based compounds in printing supports, but few cases of using them in ink jet inks. Examples of their use in ink jet inks include the use of isothiazolone or benzisothiazolone (see Japanese Laid-Open Patent Applications H11-228860 and 2000-355665, for example), and the use of alkylisothiazolones (see Japanese Laid-Open Patent Application 2002-256193, for example). However, there has been no listing of specific examples of alkylisothiazolones, nor mention of which compounding compositions would be good.
Also, particularly in the case of an aqueous ink in which a pigment ink is used, there have been instances of use polymers for the dispersion thereof, or of using macromolecular fine particles in order to improve fixing to the paper or other recording medium.
Bacteria, mold, and other such microbes therefore tend to occur more readily than with aqueous inks in which no pigment ink is used.